【作者】 李伟；

【导师】 黄玉祥；

【作者基本信息】 西北农林科技大学 ， 农业机械化工程， 2017， 硕士

【摘要】 分层深松有利于深层土壤的熟化,减少残茬、杂草的堵塞,具有较大的应用前景。本文以分层深松的理论分析为基础,使用数字化土槽试验方法,研究前铲的入土深度、铲形及入土角度对分层深松土壤扰动的影响,为分层深松机的设计提供依据,有助于深松作业质量的提高。本文的主要研究内容和结论如下。(1)土壤分层深松的理论研究。分析了分层深松条件下的土壤剪切、破碎过程,以土壤抬升体积预测模型的形式,深入探讨分层深松铲-土壤的相互作用关系;得到影响分层深松土壤扰动的主要因素为前、后铲的入土深度、铲宽(铲形)、入土角和前后铲的纵向间距。(2)不同前铲入土深度对分层深松土壤扰动的影响。采用数字化土槽试验方法,通过深松土壤扰动效果的评价指标,研究了前铲入土深度为100、150、200、250mm条件下分层深松土壤扰动效果的差异情况。EDEM仿真结果表明,与单铲深松相比,分层深松可分离、疏松不同土层的土壤,减少上下土层土壤的混合;随着前铲入土深度的增加,后铲的土壤运动范围随之减少。土槽试验结果表明,随着前铲入土深度的增加,分层深松的土壤坑形轮廓宽度和土壤蓬松度随之增大;当前铲入土深度为150mm时,分层深松的土壤扰动系数和深松深度稳定性最高;不同前铲入土深度条件下,分层深松后土垄垄沟的宽度和土壤扰动系数均大于单铲深松,土壤地表平整性和深松深度稳定性优于单铲深松,但分层深松后的土垄高度均低于单铲深松。(3)不同前铲铲形对分层深松土壤扰动的影响。以凿形铲、箭形铲和翼形铲为对象,对比研究了前铲铲形对分层深松土壤扰动的影响。结果表明,当分层深松铲的前铲为翼形铲时,土壤坑形轮廓、深松沟底和土垄垄沟的宽度、土壤蓬松度和扰动系数最大,且土壤地表平整性和深松深度稳定性最好,箭形铲次之,凿形铲最小;不同前铲铲形条件下,分层深松的土垄垄沟宽度均大于单铲深松,地表平整性和深松深度稳定性优于单铲深松,但分层深松的土壤坑形轮廓宽度和土垄高度均小于单铲深松。(4)不同前铲入土角对分层深松土壤扰动的影响。通过数字化土槽试验方法,研究前铲入土角度为15°、19°、23°、27°、31°条件下分层深松土壤扰动效果的变化。试验结果表明,分层深松后,土壤坑形轮廓宽度随前铲入土角的增大而减小;当前铲入土角为15°时,分层深松铲的土壤蓬松度、土垄高度最大;当前铲入土角为27°时,分层深松铲的土壤扰动系数最大;分层深松铲在前铲入土角为31°时的垄沟宽度最大,土壤地表平整性和深松深度稳定性最好;不同前铲入土角条件下,分层深松的土壤坑形轮廓宽度均小于单铲深松。更多还原

【Abstract】 The subsoiling in tandem can promote the soil maturation in the deep soil layer,and reduce the blocking phenomenon of crop stubble and weed,which has a good development foreground.In this paper,with the basis of the theoretical analysis of subsoiling in tandem,the digital soil-bin experiment method was used to study the influence that the depth of the front subsoiler,the front subsoiler tines and the rake angles of front subsoiler on the soil disturbance of the subsoiling in tandem.The main research contents and conclusions of this paper are as follows.(1)The theoretical analysis of subsoiling in tandem.The soil shear failure and crushing process under subsoiling in tandem conditions was analyzed,and the interaction relationship between subsoiler in tandem and soil was deeply studied fromthe prediction model of soil disturbance volume.The main factors influencing soil disturbance of subsoiling in tandem were the depth of front subsoiler,the width/shape of front subsoiler tine,the rake angle of front subsoiler and the distance between front subsoiler and rear subsoiler.(2)The influence of the depth of front subsoiler on the soil disturbance of subsoiling in tandem.With the evaluation index of soil disturbance effectiveness,the digital soil-bin experiment method was used to study the influence difference of subsoiling in tandem under thedepth of front subsoiler 100,150,200,250 mm.EDEM simulation results showed that compared with single subsoiler,subsoiling in tandem could separate and loosen the soil of different soil layers,reduce the mixture of soil of different soil layers;With the increasing depth of front subsoiler,the soil disturbance range showed a decreasing trend.The soil-bin experiment indicated that after subsoiling in tandem,the width of the soil profile and soil volume expansivity increased with the increasement of depth of the front subsoiler.The soil disturbance coefficient and the stability coefficient of subsoiling depth was the largest when the depth of the front subsoiler was 150 mm.The width of subsoiling furrow,width of soil ridge and soil disturbance coefficient of subsoiler in tandem was bigger than that of single subsoiler,soil roughness and the stability coefficient of subsoiling depth of subsoiler in tandem was bigger than that of single subsoiler,and the height of soil ridge of subsoiler in tandem was small than that of single subsoiler.(3)The influence of the front subsoiler tines on the soil disturbance of subsoiling in tandem.With the chisel tine,arrow tine and sweep tine as objects,the influence of the front subsoiler tines on the soil disturbance of subsoiling in tandemwas studied.Results showed that with the sweep tine as front subsoiler,the subsoiler in tandem had the biggest width of the soil profile,width of subsoiling furrow,the width of soil ridge,soil volume expansivity,soil disturbance coefficient,and the best soil roughness and the stability coefficientof subsoiling depth,the arrow tine took a second place,and the chisel tine was the least.With different front subsoiler tines,the subsoiler in tandem had the bigger width of soil ridge,better soil roughness and stability coefficient of subsoiling depth than single tine,while the subsoiler in tandem had the smaller width of the soil profile and the height of soil ridge than that of single subsoiler.(4)The influence of the rake angle of the front subsoiler on the soil disturbance of subsoiling in tandem.The digital soil-bin experiment method was used to study the influence of subsoiling in tandem under therake angle of front subsoiler 15°,19°,23°,27°,31°.The experiment results indicated that with the increase of the rake angle of the front subsoiler,the width of the soil profile of subsoiler in tandem reduced gradually.When the rake angle of the front subsoiler is 15°,the subsoiler in tandem had the biggest soil volume expansivity and the highest soil ridge.With 27° rake angle of front subsoiler,the subsoiler in tandem got the biggest soil disturbance coefficient.With 31° rake angle of front subsoiler,the subsoiler in tandem got the biggest width of soil ridge,and got the best soil roughness and stability coefficient of subsoiling depth.The width of the soil profile of subsoiler in tandem with different rake angles of front subsoilerwas smaller than that of single subsoiler.更多还原